Although conventionally, the therapy of a disease was generally made by an oral administration or parenteral administration of a drug was general, relatively recently a method to transdermally administer a drug into the body has been used. As a characteristic of a transdermal absorption preparation, it adheres closely for 24 to 48 hours in general, whereby absorption of a designated amount of a drug is necessary, and it is necessary that it adheres closely and does not peel off even when sweating or having a bath. In addition, it is also necessary that it can be peeled off with a peeling force in such a degree as not to be painful when peeling off, and if a pressure-sensitive adhesiveness is strong beyond necessity, hair plucking or keratin peeling occur when peeling off, while a mechanistic skin irritation due to pulling of the skin is produced. As the results, erythema occurs and in a severe case incrustation or edema formation are accompanied, whereby these last for several days after peeling off; and therefore, it is necessary to minimize these inconveniences as much as possible. In addition, it is also necessary not to let a pressure-sensitive adhesive agent remain on a skin surface after peeling off a transdermal absorption preparation from the skin.
Many of acrylic pressure-sensitive adhesive agents themselves at present have appropriate adhesive physical-properties and do not spoil the adhesive physical-properties even letting a small amount of drug be contained in them at a solubilized or crystalline states. However, although a transdermal absorption preparation using this pressure-sensitive adhesive agent has the above characteristics, there was a defect that in case of adding a large amount of a softener, a plasticizer or the like in order to improve a drug release, a cohesive force was insufficient and a glue residue occurred. Therefore, in order to get a excellent patch it is necessary to solve in particular the problem of the glue residue.
In a transdermal absorption preparation, a method to crosslink a pressure-sensitive adhesive agent has been used in order to secure an appropriate cohesive force of a pressure-sensitive adhesive layer and to remove a glue residue. For example, a method to micro crosslink the pressure-sensitive adhesive agent itself by a crosslinking agent and the like, a method to crosslink by a metal ion crosslinking, a urethane crosslinking, an epoxy crosslinking, a melamine crosslinking or a radical reaction by a peroxide compound or an electron beam irradiation is known. However, when applying such an above crosslinking method, the cohesive force was improved; however, the pressure-sensitive adhesive property was lowered due to hardening of the pressure-sensitive adhesive agent and there was a defect that a sticking property became poor.
In addition, as improvement of the above crosslinking pressure-sensitive adhesive agent is proposed a crosslinking method to let a large amount of a plasticizer (e.g. Patent documents 1 and 2) be contained. However, although in the case of this transdermal absorption preparation a shape keeping property of the pressure-sensitive adhesive layer could be raised, it had defects that a preparation design was difficult in which a pressure-sensitive adhesiveness to the skin and a cohesive force of the pressure-sensitive adhesive agent were balanced, and a drug stability was apt to become worse due to reaction of a crosslinking agent and a drug, and so on.
In addition, an adhesive agent and a pressure-sensitive adhesive preparation aiming a moderate combination of a pressure-sensitive adhesive property and a cohesive property are known (Patent document 3). However, in such a pressure-sensitive adhesive agent and a pressure-sensitive adhesive preparation, a skin sticking property, that is, a follow-up property is not necessarily sufficient.
Patent document 1: JP, B, 2700835
Patent document 2: JP, B, 3014188
Patent document 3: JP, A, 2003-213222